Characterization of nano-structured Cu–6 wt.% Zr alloy produced by mechanical alloying and annealing methods

The mechanical alloying process is used to produce nano-structured solid solution alloys, which may be further strengthened by the age-hardening process. Milling time is an important parameter during mechanical alloying. In the present research, the optimum milling time for the production of Cu–6 wt.% Zr alloy was to be determined. Cu and Zr powder mixtures were milled in a planetary ball mill for different milling times. As milled powder mixtures were investigated by SEM and XRD. Average particle sizes, lattice parameter and average crystal size were determined at different milling times. As milled powder mixtures were subsequently isothermally annealed at different temperatures and their microhardness was measured. The results showed that during milling, average particle size initially increased to a maximum value and decreased at longer times, while average crystal size continuously decreased with milling time. Lattice parameter increased with milling time. The maximum hardness value was obtained after 48 h of milling and annealed at 600 °C. Longer milling times did not improve hardness of the material.

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► Mechanical alloying and age-hardening processes were done on Cu–Zr powder mixtures.
► Max.-content of Zr in Cu-matrix was obtainable up to four times of equilibrium value.
► High hardness value was showed after age hardening treatment.
► Zr-content and sintering temp. had profound effects on the behavior of the material.